1. Field of the Invention
This invention relates to an electric stapler for binding chiefly sheets of paper placed one upon another by driving staples therethrough.
2. Description of the Prior Art
In the art of this type of electric stapler is known, for instance, the mechanism disclosed in Japanese Patent Laid-Open No. 137570/83. The electric stapler disclosed in this patent is essentially as outlined below. A magazine containing a strip of staples is provided movably up and down relative to the anvil and a slider arranged to push said strip of staples is elastically held by said magazine so as to be movable forwardly and backwardly. Above said magazine is swingably provided a working arm having a blade for driving the staples in said magazine one by one. The proximal end of said arm is elastically held by a compression spring which can expand and contract in the vertical direction. Substantially L-shaped drive arms are pivotally provided on both sides of said working arm, each of said drive arms being so arranged that the end of its horizontal portion is engaged with a roller disposed close to the fore end of said working arm. At the lower end of the vertical portion of each of said drive arms is rotatably mounted an eccentric roller secured to the corresponding one of a pair of pivotally supported crank discs which are operatively connected through gearing to a motor connected to a commercial power source by a cord.
The electric stapler of said mechanism is suited for binding pamphlets, booklets, etc., having a thickness in a certain range, but it has many problems in practical use. For instance, the mechanism for vertically moving the blade for driving the staples from the staple magazine is complicated and also necessitates many parts, which necessarily leads to a high manufacturing cost. Further, since the staple driver blade is moved up and down by the circular movements of the working arm and the drive arms on both sides thereof, the up and down movement of said blade in a vertical state may not be made smoothly, and a special mechanism is required for effecting such up and down movement of said blade in a vertical state. Moreover, since a commercial power source is required for the motor, the stapler is unusable where no commercial power source is available, and further handling of the cord makes trouble.